.\" $OpenBSD: SSL_CIPHER_get_name.3,v 1.11 2020/04/14 15:27:35 schwarze Exp $
.\" full merge up to: OpenSSL b97fdb57 Nov 11 09:33:09 2016 +0100
.\" selective merge up to: OpenSSL 61f805c1 Jan 16 01:01:46 2018 +0800
.\"
.\" This file was written by Lutz Jaenicke <jaenicke@openssl.org>,
.\" Dr. Stephen Henson <steve@openssl.org>, Todd Short <tshort@akamai.com>,
.\" and Paul Yang <yang.yang@baishancloud.com>.
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.Dd $Mdocdate: April 14 2020 $
.Dt SSL_CIPHER_GET_NAME 3
.Os
.Sh NAME
.Nm SSL_CIPHER_get_name ,
.Nm SSL_CIPHER_get_bits ,
.Nm SSL_CIPHER_get_version ,
.Nm SSL_CIPHER_get_cipher_nid ,
.Nm SSL_CIPHER_get_digest_nid ,
.Nm SSL_CIPHER_get_kx_nid ,
.Nm SSL_CIPHER_get_auth_nid ,
.Nm SSL_CIPHER_is_aead ,
.Nm SSL_CIPHER_get_id ,
.Nm SSL_CIPHER_description
.Nd get SSL_CIPHER properties
.Sh SYNOPSIS
.In openssl/ssl.h
.Ft const char *
.Fn SSL_CIPHER_get_name "const SSL_CIPHER *cipher"
.Ft int
.Fn SSL_CIPHER_get_bits "const SSL_CIPHER *cipher" "int *alg_bits"
.Ft const char *
.Fn SSL_CIPHER_get_version "const SSL_CIPHER *cipher"
.Ft int
.Fn SSL_CIPHER_get_cipher_nid "const SSL_CIPHER *cipher"
.Ft int
.Fn SSL_CIPHER_get_digest_nid "const SSL_CIPHER *cipher"
.Ft int
.Fn SSL_CIPHER_get_kx_nid "const SSL_CIPHER *cipher"
.Ft int
.Fn SSL_CIPHER_get_auth_nid "const SSL_CIPHER *cipher"
.Ft int
.Fn SSL_CIPHER_is_aead "const SSL_CIPHER *cipher"
.Ft unsigned long
.Fn SSL_CIPHER_get_id "const SSL_CIPHER *cipher"
.Ft char *
.Fn SSL_CIPHER_description "const SSL_CIPHER *cipher" "char *buf" "int size"
.Sh DESCRIPTION
.Fn SSL_CIPHER_get_name
returns a pointer to the name of
.Fa cipher .
.Pp
.Fn SSL_CIPHER_get_bits
returns the number of secret bits used for
.Fa cipher .
If
.Fa alg_bits
is not
.Dv NULL ,
the number of bits processed by the chosen algorithm is stored into it.
.Pp
.Fn SSL_CIPHER_get_version
returns a string which indicates the SSL/TLS protocol version that first
defined the cipher.
This is currently
.Qq TLSv1/SSLv3 .
In some cases it should possibly return
.Qq TLSv1.2
but the function does not; use
.Fn SSL_CIPHER_description
instead.
.Pp
.Fn SSL_CIPHER_get_cipher_nid
returns the cipher NID corresponding to the
.Fa cipher .
If there is no cipher (e.g. for cipher suites with no encryption), then
.Dv NID_undef
is returned.
.Pp
.Fn SSL_CIPHER_get_digest_nid
returns the digest NID corresponding to the MAC used by the
.Fa cipher
during record encryption/decryption.
If there is no digest (e.g. for AEAD cipher suites), then
.Dv NID_undef
is returned.
.Pp
.Fn SSL_CIPHER_get_kx_nid
returns the key exchange NID corresponding to the method used by the
.Fa cipher .
If there is no key exchange, then
.Dv NID_undef
is returned.
Examples of possible return values include
.Dv NID_kx_rsa ,
.Dv NID_kx_dhe ,
and
.Dv NID_kx_ecdhe .
.Pp
.Fn SSL_CIPHER_get_auth_nid
returns the authentication NID corresponding to the method used by the
.Fa cipher .
If there is no authentication,
.Dv NID_undef
is returned.
Examples of possible return values include
.Dv NID_auth_rsa
and
.Dv NID_auth_ecdsa .
.Pp
.Fn SSL_CIPHER_is_aead
returns 1 if the
.Fa cipher
is AEAD (e.g. GCM or ChaCha20/Poly1305), or 0 if it is not AEAD.
.Pp
.Fn SSL_CIPHER_get_id
returns the ID of the given
.Fa cipher ,
which must not be
.Dv NULL .
The ID here is an OpenSSL-specific concept, which stores a prefix
of 0x0300 in the higher two bytes and the IANA-specified chipher
suite ID in the lower two bytes.
For instance, TLS_RSA_WITH_NULL_MD5 has IANA ID "0x00, 0x01", so
.Fn SSL_CIPHER_get_id
returns 0x03000001.
.Pp
.Fn SSL_CIPHER_description
copies a textual description of
.Fa cipher
into the buffer
.Fa buf ,
which must be at least
.Fa size
bytes long.
The
.Fa cipher
argument must not be a
.Dv NULL
pointer.
If
.Fa buf
is
.Dv NULL ,
a buffer is allocated using
.Xr asprintf 3 ;
that buffer should be freed using the
.Xr free 3
function.
If
.Fa len
is too small to hold the description, a pointer to the static string
.Qq Buffer too small
is returned.
If memory allocation fails, which can happen even if a
.Fa buf
of sufficient size is provided, a pointer to the static string
.Qq OPENSSL_malloc Error
is returned and the content of
.Fa buf
remains unchanged.
.Pp
The string returned by
.Fn SSL_CIPHER_description
consists of several fields separated by whitespace:
.Bl -tag -width Ds
.It Aq Ar ciphername
Textual representation of the cipher name.
.It Aq Ar protocol version
Protocol version:
.Sy SSLv3 ,
.Sy TLSv1.2 ,
or
.Sy TLSv1.3 .
The TLSv1.0 ciphers are flagged with SSLv3.
No new ciphers were added by TLSv1.1.
.It Kx= Ns Aq Ar key exchange
Key exchange method:
.Sy DH ,
.Sy ECDH ,
.Sy GOST ,
.Sy RSA ,
or
.Sy TLSv1.3 .
.It Au= Ns Aq Ar authentication
Authentication method:
.Sy ECDSA ,
.Sy GOST01 ,
.Sy RSA ,
.Sy TLSv1.3 ,
or
.Sy None .
.Sy None
is the representation of anonymous ciphers.
.It Enc= Ns Aq Ar symmetric encryption method
Encryption method with number of secret bits:
.Sy 3DES(168) ,
.Sy RC4(128) ,
.Sy AES(128) ,
.Sy AES(256) ,
.Sy AESCGM(128) ,
.Sy AESCGM(256) ,
.Sy Camellia(128) ,
.Sy Camellia(256) ,
.Sy ChaCha20-Poly1305 ,
.Sy GOST-28178-89-CNT ,
or
.Sy None .
.It Mac= Ns Aq Ar message authentication code
Message digest:
.Sy MD5 ,
.Sy SHA1 ,
.Sy SHA256 ,
.Sy SHA384 ,
.Sy AEAD ,
.Sy GOST94 ,
.Sy GOST89IMIT ,
or
.Sy STREEBOG256 .
.El
.Sh RETURN VALUES
.Fn SSL_CIPHER_get_name
returns an internal pointer to a NUL-terminated string.
.Fn SSL_CIPHER_get_version
returns a pointer to a static NUL-terminated string.
If
.Fa cipher
is a
.Dv NULL
pointer, both functions return a pointer to the static string
.Qq Pq NONE .
.Pp
.Fn SSL_CIPHER_get_bits
returns a positive integer representing the number of secret bits
or 0 if
.Fa cipher
is a
.Dv NULL
pointer.
.Pp
.Fn SSL_CIPHER_get_cipher_nid ,
.Fn SSL_CIPHER_get_digest_nid ,
.Fn SSL_CIPHER_get_kx_nid ,
and
.Fn SSL_CIPHER_get_auth_nid
return an NID constant or
.Dv NID_undef
if an error occurred.
.Pp
.Fn SSL_CIPHER_is_aead
returns 1 if the
.Fa cipher
is AEAD or 0 otherwise.
.Pp
.Fn SSL_CIPHER_get_id
returns a 32-bit unsigned integer.
.Pp
.Fn SSL_CIPHER_description
returns
.Fa buf
or a newly allocated string on success or a pointer to a static
string on error.
.Sh EXAMPLES
An example for the output of
.Fn SSL_CIPHER_description :
.Bd -literal
ECDHE-RSA-AES256-GCM-SHA256 TLSv1.2 Kx=ECDH Au=RSA Enc=AESGCM(256) Mac=AEAD
.Ed
.Pp
A complete list can be retrieved by invoking the following command:
.Pp
.Dl $ openssl ciphers -v ALL:COMPLEMENTOFALL
.Sh SEE ALSO
.Xr openssl 1 ,
.Xr ssl 3 ,
.Xr SSL_get_ciphers 3 ,
.Xr SSL_get_current_cipher 3
.Sh HISTORY
.Fn SSL_CIPHER_description
first appeared in SSLeay 0.8.0.
.Fn SSL_CIPHER_get_name ,
.Fn SSL_CIPHER_get_bits ,
and
.Fn SSL_CIPHER_get_version
first appeared in SSLeay 0.8.1.
These functions have been available since
.Ox 2.4 .
.Pp
.Fn SSL_CIPHER_get_id
first appeared in OpenSSL 1.0.1 and has been available since
.Ox 5.3 .
.Pp
.Fn SSL_CIPHER_get_cipher_nid ,
.Fn SSL_CIPHER_get_digest_nid ,
.Fn SSL_CIPHER_get_kx_nid ,
.Fn SSL_CIPHER_get_auth_nid ,
and
.Fn SSL_CIPHER_is_aead
first appeared in OpenSSL 1.1.0 and have been available since
.Ox 6.3 .
.Sh BUGS
If
.Fn SSL_CIPHER_description
cannot handle a built-in cipher,
the according description of the cipher property is
.Qq unknown .
This case should not occur.
